IT’S the condiment that divides a nation but thanks to the first all-Edinburgh Scottish Cup final since 1896, chip shop sauce could be about to take off throughout the country.

IT’S the condiment that divides a nation but thanks to the first all-Edinburgh Scottish Cup final since 1896, chip shop sauce could be about to take off throughout the country.

It might surprise natives of the capital that the sauce is actually made on the outskirts of Glasgow.

Walter Black’s company have been producing the condiment for four generations and as far back as any of his family can remember it has always been much more popular in Edinburgh and the east coast.

But that could all change when the 50,000 fans take over Glasgow next month for the Hibs v Hearts Scottish Cup clash.

Chippies near Hampden are already stocking up in advance of the green and maroon invasion, meaning a boom for the Cambuslang firm.

So to make sure Walter, his son and operations manager Stuart Black, and the rest of the employees at the hi-tech plant can cope with the demand, I decided to help out as a saucer's apprentice.

The family firm may not be as well known as KFC, but the recipe for the condiment is just as big a secret as Colonel Sanders’ mystery batter.

The recipe has been passed down the generations since Walter’s grandfather, who founded the company in 1901, created the Gold Star sauce in the 20s.

And with the exception of a few changes to the manufacturing processes, the formula is the same.

But despite all the secrecy, Walter was brave enough to let me near the bubbling vats to show me the complicated process from start to finish.

The sauce begins life as huge sacks and tubs of ingredients which include wheat flour, acetic acid and spices such as ginger and cinnamon.

Specialists make sure the recipe is just right, then the ingredients are poured into the giant cooking pots and left to bubble away for hours.

I wanted a closer look at the huge 1000 litre batches and found myself nose deep in a kitchen which must be one of the most aromatic in Scotland.

The air was so thick with hot tangy fumes that you could just as well be swimming in the stuff.

Manning the kitchen was Iain McQuade, who smiled as I made the rookie mistake of peering into the fermenting pot – my eyeballs felt like they had turned into pickled onions.

Once I recovered, it was back to the important job of getting the sauce out to the good people of Scotland.

Once the sauce is cooked, Gold Star technical manager Diane Campbell and laboratory co-ordinator Colin Forman, get all scientific.

They run a series of tests on samples checking acidity, salt, pH levels and then, most important of all, they taste it.

Diane has been taste and lab testing sauce for 15 years.

She said: “For us, the quality and safety of the product is paramount and this is a very important part of the process.

“It’s a great product, and I am always delighted to see it on the shelves and being in demand.

“I’d be delighted if the Edinburgh teams’ cup final made more people in the rest of Scotland enjoy the sauce.”

Once it has passed quality control, the finished product is pumped into cooling vats, awaiting bottling.

An incredible 60,000 litres of sauce leave the factory every week.

As well as chip shops in the east they also supply supermarkets such as Asda and Sainsbury’s, who actually suggested the rebranding of the product as Chip Shop Brown Sauce to make it more identifiable.

Walter and Stuart’s firm produces more than 500 different products, including sauces, pickles and condiments, but the brown sauce remains their most famous.

Stuart said: “We do sell brown sauce in the west, but nowhere near as much as on the east coast, but we don’t know why that is.

“There is not as much difference in the sales figures when it comes to sales in shops, but we have never worked out why vinegar is more popular elsewhere.”

Walter added: “I’m delighted all the Edinburgh fans are coming through and hopefully there will be a big sales boost for sauce.

“Maybe more people through this way will catch on to it – and as far as my business is concerned, the more the merrier.”